The invention relates to a light-source tracking system and more particularly to a system which uses orthogonal triangular interferometric systems which provide modulation transfer functions containing carrier frequencies which are used to provide the tracking signal.
Prior art light-source tracking systems formed an image of the object being tracked on a detector and sensed the position of image on the detector to provide the tracking signal. The sensing was achieved by using a scanning reticle in conjunction with amplitude sensitive detectors; a position sensitive detector in the form of a solid state device which produces a signal proportional to the location of the incident light on the device, or a television type of device.